The invention relates to a target-and-cathode arrangement for a cathode sputtering apparatus having a continuous form of cathode with a target body which can be coupled to a cooling system by means of a releasable fastening device.
In production plants for the preparation of substrates that are to be coated, a routine changing of the targets is necessary on account of the constant bombardment of the target bodies with ions and the resultant sputtering of the target bodies. The down time necessitated thereby has to be kept as brief as possible from the viewpoint of the economic utilization of such machines. However the target changing is often complicated by the fact that the target bodies are in direct contact with a cooling system. When targets are replaced, the cooling system usually has to be opened up, which necessitates tedious cleaning operations.
The cooling of a target body is necessitated by its being constantly bombarded with ions, which exposes the target body to great thermal stress. As a precaution against embrittlement and overheating of the target material, provision must be made for an especially good heat transfer between target body and cooling system. This is usually accomplished by putting the entire surface of the bottom of the target body in contact with a cooling surface whose bottom in turn is in contact with a cooling liquid.
Known cooling systems have a plate between the cooling system and the target body, but when the target is replaced the plate also has to be raised so that the cooling channel will be open, and it calls for the replacement or cleaning of any gaskets that may be present. Changing the target bodies thus simultaneously requires intervention in the cooling system, which calls for an enormous additional amount of work. Furthermore, when reassembling the risk of leakage in the cooling system is very great, so that a water-tightness and vacuum-tightness test must be performed in order to assure trouble-free continued operation.
It is not only the opening of cooling systems that is involved in the replacement of targets in known cathode sputtering apparatus, but depending on the structural characteristics, the magnet systems of the apparatus are also exposed to external mechanical influences. Accidental maladjustment or damage to the magnets can adversely affect the stability of the plasma.